550  Stamp
How many stamps? 1

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There are 120 stamps which are 7-cent stamps and 9-cent stamps. Altogether they cost 940 cents. How many 7-cent stamps are there?



There are 150 stamps which are 5-cent stamps and 4-cent stamps. Altogether they cost 690 cents. How many 5-cent stamps are there?



There are 190 stamps which are 6-cent stamps and 5-cent stamps. Altogether they cost 1070 cents. How many 6-cent stamps are there?



There are 170 stamps which are 3-cent stamps and 4-cent stamps. Altogether they cost 580 cents. How many 3-cent stamps are there?



There are 270 stamps which are 7-cent stamps and 8-cent stamps. Altogether they cost 2020 cents. How many 7-cent stamps are there?



There are 170 stamps which are 7-cent stamps and 5-cent stamps. Altogether they cost 1050 cents. How many 7-cent stamps are there?



There are 180 stamps which are 6-cent stamps and 7-cent stamps. Altogether they cost 1180 cents. How many 6-cent stamps are there?



There are 140 stamps which are 7-cent stamps and 4-cent stamps. Altogether they cost 830 cents. How many 7-cent stamps are there?



There are 230 stamps which are 7-cent stamps and 5-cent stamps. Altogether they cost 1410 cents. How many 7-cent stamps are there?



There are 190 stamps which are 7-cent stamps and 4-cent stamps. Altogether they cost 1090 cents. How many 7-cent stamps are there?



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550    70 90 120 100 140 ( 520 )   100 80 90 130 110 ( 510 )   [[ 1030 ]]